An Autonomous System (AS) is a small-sized network, in the Internet, capable of autonomously determining a routing protocol that is used in the system. The AS system may be a simple network unit, or may be a network group including multiple network units controlled by at least one network management device.
The BGP is a routing protocol used between AS systems and is mainly used to exchange routing information between the AS systems, so that after obtaining the routing information, a controller builds a propagation path of data between the AS systems.
With unceasing maturity and development of network technologies, centralized network control becomes a future network development trend. There are two types of devices in a centralized control network: a controller (Controller) and a forwarder (Forwarder). The controller is responsible for performing centralized control on the network and delivering a forwarding entry to the forwarder, and the forwarder performs packet matching and forwarding. In the prior art, no technical solution can effectively implement collection of a BGP logical topology between forwarders by the controller, which is unfavorable for the controller to manage forwarders running the BGP protocol.